//基本类型
var sport: string = 'football';
var id: number = 5;
var isMarried: boolean = true;
var years: string | number;
years = '20';
years = 21;

//引用类型
var my_name = new String('guo');
var my_id = new Number(5);
var my_flag = new Boolean(true);

//any
let age: any = '20';
age = 21;
age = {
    years: 21,
    month: 6
}

